Field of the Invention
The present invention relates to a method and a magnetic resonance apparatus for the automated analysis of the raw data of a spectrum.
Description of the Prior Art
It is known that magnetic resonance spectra offer the possibility of examining metabolic processes in human bodies. Furthermore, the recording (detection or acquisition) of spectra, and in particular magnetic resonance spectra, from materials is known, in order to derive conclusions from these spectra regarding the aging state of the materials, for example.
For this purpose, either signal intensities for specific resonances are determined, or relative signal intensity ratios are formed. These signal intensities or relative signal intensity ratios are characteristic for a specific state of the object examined, because the signal intensity of a resonance correlates directly to the concentration of the material in question from which the resonance originates.
In order to determine such signal intensities, the area under the spectrum in a specific frequency range, specifically a so-called peak, is measured. The use of a single signal intensity is frequently not possible because the signal intensity is dependent on numerous factors, including the echo time, the repetition interval, the receiver gain, the measurement sequence used for the recording, and numerous other variables. For this reason, typically, signal intensity ratios for two resonances in a spectrum are compared with one another.
The signal intensities are typically analyzed by matching a known spectrum thereto.
Aside from the examination of materials, MR spectra are also used in order to examine metabolite concentrations or ratios in tissues of patients, because these concentrations are normally changed by illnesses or pathologies in a defined manner. It is known that, for example, in healthy brain tissue, the relative signal ratio of N-acetylaspartic acid (NAA) to creatine (KR in German) lies at 2.0, while in tumor tissue, it drops to values of less than 1.6. Before executing the diagnostics, the appropriate published values must first be obtained. The same applies, as a matter of course, for materials control or examination.
This results in either the same spectrum in numerous persons being analyzed leading to different results, or the analysis of one spectrum being extremely complex and time consuming. The analysis results thus exhibit a certain inherent uncertainty.